Lifting card



June 7, 1960 A- A. G. REJDIN YETAL 2,939,937

LIFTING CARD Filed Dec. 19, 1957 Fig.3

Fig. 7

Fig. 4

IN Vf/VT'ORS 191?! 6 x51. Cwwvnn Ream/1v U tedst rss Page 0.7

2,939,937 LIFIING Arne Axel Gunnar Rejdin, Sollentuna, and Sten Lennart Melker Wahl, Bromma, Sweden, assignors to Telefonaktiebolaget L M Ericsson, Stockholm, Sweden, a corporation of Sweden Filed Dec. '19, 1957, Ser. No. 703,900 Claims priority, application Sweden Feb. 15, 1957 Claims. (Cl.200- 166) The present invention refers to a lifting card of the kind used for actuating spring groups of relays, crossbar switches and'the like.

Ordinarily the lifting card is usually located in slots punched in the springs. The lifting card is, at least along one edge, provided with slits, the width of which corresponds to the thickness of the springs, and by means of which it engages the springs.

In conventional devices the lifting card is locked against displacement in the longitudinal direction of the springs by the top spring slot being shorter than the slots of the other springs, so that the lifting card rests against an edge of the top spring slot, while at the lower end it might be locked against displacement in the longitudinal direction of the springs, for example by engaging a member provided for actuating the lifting card. In order to avoid having to adjust the springs after the mounting of the spring group, the springs usually arcuately performed to lightly tension the springs so that each one of them rests against one edge of the respective slit of the card with a light pressure, opposed to the lifting direction. It is possible that one or several springs might lose this pretension and tend to bend in the lifting direction so as to rest against the upper edge of the slit. The card impedes the bending of all the springs, except for the top one that is not engaged by any slit of the card.

The known device is thus subject to two disadvantages. First of all, the top spring has to be provided with a slot shorter than that of the other springs signifying the necessity of manufacturing two types of springs. Secondly, the card does not limit the movement of the top spring in the lifting direction.

The object of the invention is to eliminate these disadvantages. The lifting card made in accordance with the present invention makes it possible to use a uniform spring, and limits the upward movement of the top spring as well as the other springs. This is achieved by the lifting card being provided, on one side of the end portion adjacent to the top spring, with a projection, that on the one hand forms a retaining surface for the upper surface of said spring, and on the other hand forms a contact surface for one edge of the slot, while it has on the opposite side a cut out, the one edge of which forms a retaining surface for the lower surface of the spring, which retaining surface is parallel to the one arranged for the upper surface. The size of the cut out is such that the largest width of the end portion of the card is less than the length of the slot, so that the spring can be slipped over said end portion.

The invention will be further described by means of an embodiment with reference to the attached drawing, in which Fig. 1 shows the design of a conventional lifting card, Fig. 2 shows the design of the lifting card according to the invention, Fig. 3 shows a side view of the spring group with the lifting card and Fig. 4 shows a top view of the arrangement according to Fig. 2.

In the drawing, a contact spring group consisting of ten movable springs 2 is shown to include a lifting card 2,939,937 Patented June 7, 1960 2 1. The contact springs are fixed to a base plate 3 by means of insulating spacers, and are intended to be carried by the lifting card in the upward direction into contact with the fixed contact members 4.

The springs are provided with slots 6, through which the lifting card is extended, which card is provided with slits 7, with which the springs can engage. The lower end of the card engages a formed spring 5 that is fixed to the base plate and prevents this end of the card from moving in one longitudinal direction of the springs. At the upper end the card has a projection 8 at the one side. This projection has a cut out with two perpendicularly related edges 9 and 10 which form contact surfaces for the top spring. The edge 9 forms a retaining surface for the upward movement of the spring, the

edge 10 restingv against an edge of the spring slot and preventing movement of the upper end of the card in the opposite longitudinal direction of the springs. At the other side the end portion has a cut out, the one edge of which'for'rns a supporting surface 11 for the lower surface of the spring, the position of which thus is fixed in relation to the card. Through the engagement of the spring 5 and the contact with the edge of the top spring in the slot the lifting card is retained in its position. The size of the cut out is chosen in such a manner, that the largest width is smaller than the length of the slot, so that the spring can he slipped over the end portion of the card.

During assembly of the spring group the card is positioned before the mounting of the top spring, whereafter the latter is slipped over the projecting part of the card and fixed to the spring group.

We claim:

1. In a switching device having a plurality of substantially stationary contacts and a plurality of coacting contact springs stacked with respect to each other, each spring having a terminal contact at one end and being secured at the other end in a fixed position by insulation means, all of said contact springs having a uniformly located, longitudinal slot of equal size intermediate the opposite ends thereof, a longitudinally movable lifting card of insulation material extending through all of said slots, lifting projections integral with one edge of said lifting card facing one end of each of said spring slots, one projection underlying each spring for flexing the same in one direction into engagement with the corresponding stationary contact in response to movement of said lifting card, and a first bearing portion integral with one end of said lifting card overlying the upper surface of said one end of the uppermost spring in the stack to secure said lifting card against longitudinal movement in a direction opposite to said one direction.

2. A switching device as set forth in claim 1 and further comprising a second bearing portion integral with the edge of said lifting card opposite to said lifting projections and adjacent to said one end of said lifting card, said second bearing portion in abutment with the opposite end of the slot in said uppermost spring to secure said one end of said lifting card against lateral displacement thereof longitudinally of said springs relative to said slots.

3. A switching device as set forth in claim 2 and further comprising locking means associated with the opposite end of said lifting card to impede lateral displacement of said opposite end of said lifting card below the lowermost spring of said stack.

4-. A switching device as set forth in claim 3 wherein said second bearing portion projects laterally outwardly from said opposite edge of said lifting card, said one edge of said lifting card at said one end defining a recess opposite said second bearing portion, and the width of said lifting card between said second bearing portion 3 and said recess being smaller than the length of said slot in said uppermost spring.

5. In a switching device having a plurality of substantially stationary contacts and a plurality of coacting contact springs stacked with respect toeach other, each spring having a terminal contact at one end and being secured at the other end in a fixed position by insulation means, all of said contact springs having a uniformly located longitudinal slot of equal size intermediate to the opposite ends thereof, a lifting card of insulation material extending through all of said slots, lifting projections in tegral With one edge of said lifting card facing one end ,of each of said spring slots, one projection underlying each spring for flexing the same in one direction into engagement with the corresponding stationary contact in response to movement of said lifting card, a first bearing portion integral with one end of saidlifting card overlying the upper surface of the uppermost spring in movement relative to said stack in a direction opposite to said one direction, a second bearing portion integral with the 'edge' of said lifting card opposite to said lifting projections andadjacent to said one end of said lifting card, said second bearing portion being in abutthe stack to secure said lifting card against longitudinal ment with the opposite end of said slot in said uppermost spring securing said one end of said lifting card against lateral displacement thereof longitudinally of said springs relative to said slots, locking means associated with the opposite end of saidlifting card to impede lateral displacement of said opposite end of said lifting card below the lowermost spring of said stack, said second bear.- ing portion projecting laterally outwardly from said opposite edge of said lifting card, said one edge of said lifting card at said one end defining arecess opposite said second bearing portion, the width of said lifting card be tween said second bearing portion and said recess being smaller than the length of said slot in said uppermost spring, and said lifting card including slots intermediate said lifting projections of slightly greater width than the thickness of each of said springs.

References Cited intthe file of this patent UNITED STATES PATENTS Mrs-d 

